On Linux when IPv6 is disabled, one would not expect Dnsmasq to bind
the IPv6 wildcard.
This patch adds a condition to the wildcard bind function, which checks
on Linux if IPv6 is disabled.
v2: fix return value of is_ipv6_disabled() with IPv6 support not compiled in
Signed-off-by: Matthias May <matthias....@westermo.com>
Signed-off-by: Zefir Kurtisi <zefir.kurt...@westermo.com>
---
src/dnsmasq.h | 1 +
src/network.c | 24 +++++++++++++-----------
src/util.c | 22 ++++++++++++++++++++++
3 files changed, 36 insertions(+), 11 deletions(-)
diff --git a/src/dnsmasq.h b/src/dnsmasq.h
index 4220798..2cfb1cb 100644
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -1292,6 +1292,7 @@ int read_write(int fd, unsigned char *packet, int size,
int rw);
void close_fds(long max_fd, int spare1, int spare2, int spare3);
int wildcard_match(const char* wildcard, const char* match);
int wildcard_matchn(const char* wildcard, const char* match, int num);
+int is_ipv6_disabled(void);
#ifdef HAVE_LINUX_NETWORK
int kernel_version(void);
#endif
diff --git a/src/network.c b/src/network.c
index c7d002b..0d35fb7 100644
--- a/src/network.c
+++ b/src/network.c
@@ -990,19 +990,21 @@ void create_wildcard_listeners(void)
l = create_listeners(&addr, !!option_bool(OPT_TFTP), 1);
- memset(&addr, 0, sizeof(addr));
+ if (!is_ipv6_disabled()) {
+ memset(&addr, 0, sizeof(addr));
#ifdef HAVE_SOCKADDR_SA_LEN
- addr.in6.sin6_len = sizeof(addr.in6);
+ addr.in6.sin6_len = sizeof(addr.in6);
#endif
- addr.in6.sin6_family = AF_INET6;
- addr.in6.sin6_addr = in6addr_any;
- addr.in6.sin6_port = htons(daemon->port);
-
- l6 = create_listeners(&addr, !!option_bool(OPT_TFTP), 1);
- if (l)
- l->next = l6;
- else
- l = l6;
+ addr.in6.sin6_family = AF_INET6;
+ addr.in6.sin6_addr = in6addr_any;
+ addr.in6.sin6_port = htons(daemon->port);
+
+ l6 = create_listeners(&addr, !!option_bool(OPT_TFTP), 1);
+ if (l)
+ l->next = l6;
+ else
+ l = l6;
+ }
daemon->listeners = l;
}
diff --git a/src/util.c b/src/util.c
index 5f13027..5cd461f 100644
--- a/src/util.c
+++ b/src/util.c
@@ -787,6 +787,28 @@ int wildcard_matchn(const char* wildcard, const char*
match, int num)
return (!num) || (*wildcard == *match);
}
+#ifndef HAVE_LINUX_NETWORK
+/* implement for other platforms */
+int is_ipv6_disabled(void)
+{
+ return 0;
+}
+#else /* HAVE_LINUX_NETWORK */
+int is_ipv6_disabled(void)
+{
+ FILE *f;
+ char *fname = "/proc/sys/net/ipv6/conf/all/disable_ipv6";
+ char buf[4];
+ int ipv6_disabled = 1;
+ if ((f = fopen(fname, "r"))) {
+ if (fgets(buf, 4, f))
+ ipv6_disabled = atoi(buf) == 1;
+ fclose(f);
+ }
+ return ipv6_disabled;
+}
+#endif /* HAVE_LINUX_NETWORK */
+
#ifdef HAVE_LINUX_NETWORK
int kernel_version(void)
{
--
2.27.0
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